Snow Monkeys Make Smart Choices

Regenstein Macaque Forest, opened in April 2015, was designed with Japanese macaques (or snow monkeys) in mind. This state-of-the-art habitat was intended to be a place where zoo visitors could see the monkeys in a landscape that resembled their native coastal forests in Japan, and where Lincoln Park Zoo scientists could get insights into the monkeys’ minds. Most importantly, the habitat was intended to be a place where the monkeys could experience great welfare in a complex and dynamic environment with a multitude of choices for how and where to spend their time, as they would in the wild.

Although snow monkeys are the northernmost living non-human primate and well-adapted for a wide range of temperatures, it was important to make sure they had ways to keep comfortable in the extreme temperatures of Chicago’s winters and summers. Thus, one key design feature of the modern Regenstein Macaque Forest was the inclusion of “micro-climates” that provided the monkeys with several options for keeping comfortable in their new habitat. In theory, the monkeys could choose their exposure to sunlight, wind, rain or snow, and decide for themselves where and how to find comfort through their use of features such as the temperate water stream, hot spring, hidden fans, 45-50-foot-tall trees, diverse natural landscaping, and climate-controlled rocky outcrops that are specially designed to provide warmth or cooling in seasonal extremes.

Regenstein Macaque Forest has proven successful for the visitors’ experience and for zoo scientists who have collected over a thousand hours of quality observational data. This puts us in the position to ask whether the monkeys are utilizing their habitat in the ways we intended, for example, by using the micro-climates to keep themselves warm in the winter and cool in the summer. We have now analyzed over a year of data on what surfaces the monkeys spend their time on, and find that, yes, they are making smart and seemingly intentional choices! When temperatures are very cold they head to the climate-controlled rocks for warmth. Likewise, when the temperatures are very warm they head to those same rocks to keep cool and often shaded. However, when temperatures are moderate, the monkeys spend more time on the grass and other natural surfaces.

This graph shows that when the temperatures are cool (less than 40 degrees) or warm (greater than 70 degrees) the macaques use their climate-controlled rocks to keep comfortable.

The Regenstein Macaque Forest habitat that visitors see is more than 7,000 square feet in size. Did you also know there is an adjacent behind-the-scenes indoor/outdoor area that provides the snow monkeys with an additional 3,742 square feet of animal space? Anytime the forecast calls for weather outside of moderate conditions (for example, above 85° F or below 40° F, or during rain or snow) the snow monkeys have access to their behind-the-scenes area in case they want to retreat to this completely sheltered and private area. However, when given this choice, our data tells us that the snow monkeys are visible to zoo guests 84 percent of the time. In other words, the snow monkeys choose the main habitat as their preferred location!

This graph shows that when temperatures are extreme and the macaques have the choice to spend time in their outdoor habitat or behind-the-scenes, they largely prefer to be outside.

The Regenstein Macaque Forest design team spent months researching, brainstorming and carefully planning the exhibit features. While we all hoped to have designed a habitat in which the monkeys would keep comfortable, it’s great to be able to look at the scientific data and see they are making smart choices to keep comfortable in their home.

Katherine Cronin, Ph.D.
Research Scientist

Maureen Leahy
Curator of Primates